Internal combustion engines, such as diesel, gasoline or natural gas engines, may be used to power various different types of machines, such as on-highway trucks or vehicles, off-highway machines, earth-moving equipment, generators, aerospace applications, stationary equipment such as power plants, and the like. In general terms, internal combustion engines are supplied with a mixture of air and fuel, which is ignited at specific timing intervals within a combustion chamber in order to generate mechanical energy, such as reciprocation of a piston within the combustion chamber, and ultimately rotational output torque through a crankshaft capable of driving or operating the associated machine. There are various ongoing efforts to improve the efficiency of the engine and the overall productivity of the associated machine. One possible solution for achieving such improvements lies within the fuel delivery system of the engine.
In general, the fuel delivery system is responsible for taking fuel from a reservoir, and introducing the fuel into the combustion chambers, where the fuel will be mixed with air and ignited. More particularly, the fuel is typically introduced into the combustion chamber through a network of fuel pumps, valves and injectors. For instance, fuel from a fuel tank may be pressurized by a pump chamber, pumped into a common fuel rail through a solenoid valve, and sprayed into a combustion chamber through fuel injectors. Increasing the inlet curtain area of the solenoid valve has been determined to provide higher volumetric efficiency. However, increasing the curtain area may also increase the amount of travel of the solenoid valve, and thus the amount electrical energy needed to actuate the solenoid valve, such as in fuel pumps which electrically actuate the solenoid valve to move between the fully opened and fully closed positions.
Various improvements to solenoid valve assemblies and actuation arrangements are conventionally available. One improvement related to valve assemblies is disclosed in U.S. Pat. No. 7,422,166 (“Hoffman”). Hoffman is aimed at overcoming the adverse effects of valve-bounce in fuel injectors, and discloses a solenoid valve for a fuel injector that is separated into two independent parts, such as an armature and a pintle. In particular, rather than having a single solenoid valve that is actuatable between opened and closed valve positions, Hoffman provides an actuatable armature that is physically separated from the valve or pintle so that any valve bounce does not affect the actual delivery of the fuel. While Hoffman may alleviate some drawbacks associated with valve actuation, Hoffman still relies on its solenoid to move through its full range of motion to actuate the armature. Moreover, Hoffman does not reduce the amount of energy that is used to control the solenoid.
In view of the foregoing disadvantages associated with conventional fuel pumps and associated solenoid valve assemblies, a need exists for a solution which is not only capable of maintaining higher volumetric efficiencies, but also capable of conserving energy while doing so. In particular, there is a need for a valve assembly and an actuation arrangement which maintains large inlet valve curtain areas without requiring additional work by a solenoid to realize the enlarged curtain areas. Furthermore, there is a need for a simplified solution that can be rather easily implemented or retrofitted onto existing fuel pump layouts so as not to require drastic redesigns. The present disclosure is directed at addressing one or more of the deficiencies and disadvantages set forth above. However, it should be appreciated that the solution of any particular problem is not a limitation on the scope of this disclosure or of the attached claims except to the extent expressly noted.